Introduction 

The India-Pakistan relationship has been characterized by persistent tensions since the partition of 1947, with Kashmir remaining the central point of contention. Recent escalations, marked by the 22nd April, 2025 Pahalgam terror attack and India's retaliatory "Operation Sindoor" on 7th May, 2025, have brought the conflict under renewed international legal scrutiny.

Jus ad Bellum: Legal Grounds for Use of Force 

The UN Charter Framework 

• The cornerstone of modern international law regarding the use of force is Article 2(4) of the UN Charter, which states: "All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations." 
• This prohibition is considered a peremptory norm (jus cogens) of international law. 
• The Charter provides only two explicit exceptions to this prohibition: 
  • Self-defense under Article 51: 
    • "Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security." 
  • UN Security Council authorization under Chapter VII for actions to maintain or restore international peace and security. 
    • India has framed "Operation Sindoor" explicitly within the Article 51 framework, citing its inherent right to self-defense following the Pahalgam terror attack.  
    • This position raises crucial legal questions about attribution, necessity, and proportionality.

Armed Attacks by Non-State Actors 

• A critical legal question is whether terrorist attacks can constitute an "armed attack" triggering the right to self-defense against a sovereign state.  
• The International Court of Justice (ICJ) addressed this issue in the Nicaragua v. United States case (1986), establishing that an armed attack by non-state actors must be of "sufficient gravity" and attributable to a state to trigger self-defense against that state. 
• The ICJ ruling holds that support given by a state to non-state actors through "financial support, training, supply of weapons, intelligence and logistical support" constitutes "a clear breach of the principle of non-intervention."  
• This principle was reinforced in UN General Assembly Resolution 3314, which defines aggression to include: "Sending by or on behalf of a State of armed bands, groups, irregulars or mercenaries, which carry out acts of armed force against another State of such gravity as to amount to acts of aggression." 
• India's legal position relies on establishing that: 
  • The Pahalgam attack was of sufficient gravity (26 civilian casualties). 
  • The attack is attributable to Pakistan through its alleged support of terrorist outfits.  

Anticipatory Self-Defense and the Caroline Test 

• While Article 51 refers to self-defense "if an armed attack occurs," customary international law recognizes a limited right to anticipatory self-defense.  
• This principle derives from the Caroline incident of 1837, establishing what is known as the Caroline test: the threat must be "instant, overwhelming, leaving no choice of means, and no moment for deliberation." 
• India's missile strikes, coming after the Pahalgam attack, do not invoke anticipatory self-defense but rather responsive self-defense.  
• However, India's new position that "any future act of terror will be treated as an act of war" suggests a potential shift toward a more expansive interpretation of self-defense that could include anticipatory elements. 

Bilateral Treaties and Agreements 

The Line of Control and the Simla Agreement 

• The Line of Control (LoC), established following the 1971 Indo-Pakistan War and formalized in the 1972 Simla Agreement, serves as a de facto military border.  
• The Simla Agreement stipulates that neither side shall unilaterally alter the line, and crossing the LoC by military forces constitutes a violation of this bilateral agreement. 

Operation Sindoor, India's missile strikes across the LoC raise questions about compliance with the Simla Agreement, though India argues that targeting terrorist infrastructure rather than Pakistani military positions represents a distinct legal situation. 

International Accountability Mechanisms 

International Court of Justice (ICJ) 

• The ICJ adjudicates disputes between states. In the Nicaragua case, the ICJ ordered reparations for damages caused by violations of international law.  
• This precedent suggests potential avenues for legal redress between India and Pakistan, though political realities make such cases difficult. 
• Neither India nor Pakistan has accepted the compulsory jurisdiction of the ICJ without reservations, limiting the court's role unless both parties consent to its jurisdiction in a specific case. 

International Criminal Court (ICC) 

• The ICC prosecutes individuals for war crimes, crimes against humanity, genocide, and aggression. 
• Neither India nor Pakistan are parties to the Rome Statute, placing them outside the ICC's jurisdiction unless the UN Security Council refers a situation to the court—a politically unlikely scenario given geopolitical alignments, particularly China's support for Pakistan. 

Extradition Challenges 

• India and Pakistan lack an extradition treaty, complicating efforts to hold individuals accountable for terrorism.  
• India's request for Hafiz Saeed's extradition in 2023 failed due to this absence. 
• Without a treaty, cooperation depends on domestic laws and international norms, creating significant gaps in accountability.

Contemporary Parallels: Lessons from Recent Conflicts 

Ukraine Conflict 

• Russia's 2022 invasion of Ukraine was widely condemned as a violation of Article 2(4) of the UN Charter.  
• Russia's claims of self-defense and protection of Russian-speaking populations were rejected by the UN General Assembly and the ICJ, reinforcing the narrow interpretation of permissible uses of force under international law. 

Israel-Palestine Conflict 

• Israel has invoked Article 51 to justify actions against Hamas, claiming self-defense against non-state actors operating from Gaza.  
• This parallel demonstrates the complex legal questions surrounding self-defense against non-state actors and the application of International Humanitarian Law in asymmetric conflicts. 

Conclusion 

The India-Pakistan conflict presents a complex intersection of international legal principles concerning the use of force, state responsibility, humanitarian law, and bilateral agreements. India's recategorization of terrorism as an "act of war" signals a significant shift in its approach, potentially reshaping the application of international law in this long-standing conflict.